Fix and update french translation

[mleduque]

• It seems some of the fixes and updates from https://github.com/subtledoctor/SubtleD_Spell_Tweaks/releases/tag/1.7.2 were lost when the 2.0 version was created, so this restores them
• If I understand correctly, the french translation for TnB pull request was merged, transferred here for "The Big Reorganization". But it was an old version of my TnB translation attempt (made for 0.9.39 AFAIR) and I had a more recent for 0.9.49 (eternally) nearly ready that I hadn't finished to test, I updated the SD_spell part here

(Note, the TnB is still terminally broken and needs work for v1.0+)